This invention relates to a method for monitoring the condition of an interconnection network, in which method monitoring cycles are carried out for checking the condition of interconnection interfaces, a counter specific to each interconnection interface is provided, and the counter is preset to a predetermined initial value. The invention further relates to monitoring equipment for an interconnection network, this equipment comprising a monitoring unit for checking the condition of interconnection interfaces, means for giving an alarm, and a counter specific to each interconnection interface.
This invention is related with monitoring and maintenance of interconnection networks, such as interconnections connected to a telephone exchange, or connections used for telecommunication. The function of the maintenance systems for interconnection networks is to monitor the interconnections connected with the exchanges and manage the failure situations occurring in them. When a monitoring system detects a failure, an alarm is given of it. The publication ITU-T Recommendations Q.542 (International Telecommunications Union) sets forth recommendations about how a monitoring system should react to various failure situations detected in an interconnection network.
A maintenance system must give an alarm when a certain number of alarms occur in an interconnection within a certain time. Occasional momentary failures occurring in interconnections must not cause an alarm. Therefore, the monitoring system must be capable of filtering alarms in accordance with the ITU-T recommendations. The aim is thus a delayed reaction, like the hysteresis phenomenon.
A solution is previously known, in which false alarms are avoided by storing interconnection interface-specific monitoring data in a buffer; i.e., each time when the operation of a certain interconnection interface is checked, the result of the check is stored in a buffer. Thus, an interconnection interface-specific list of the results of monitoring is formed in the buffer. An alarm is given only in the case where a failure is detected in a certain interconnection interface during several monitoring cycles. The weakness of this prior art method is that it requires a very large memory capacity and resources, such as processor time for managing and utilizing the data stored in the buffer. The more complex the filtering conditions are to be followed in the system, and the more interconnection interfaces are to be monitored in the system, the more resources are consumed. The need of resources is due to the fact that the monitoring system must read the information (a list) on every single interconnection interface from the buffer during a monitoring cycle, after which the information on the single interconnection interface must be interpreted on the basis of the set filtering condition, and only after this, the monitoring system may conclude whether it should give an alarm relating to the interconnection interface in question.